OFFSET
0,6
LINKS
Matthew House, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (3, -4, 4, -4, 4, -4, 4, -3, 1).
FORMULA
From R. J. Mathar, Apr 15 2010: (Start)
a(n) = +3*a(n-1) -4*a(n-2) +4*a(n-3) -4*a(n-4) +4*a(n-5) -4*a(n-6) +4*a(n-7) -3*a(n-8) +a(n-9).
G.f.: x^4*(x^2+1-x)/ ((1-x)^3 * (x^2+1) * (x^4+1)). (End)
MAPLE
seq(floor(binomial(n, 2)/4), n=0..51); # Zerinvary Lajos, Jan 12 2009
MATHEMATICA
LinearRecurrence[{3, -4, 4, -4, 4, -4, 4, -3, 1}, {0, 0, 0, 0, 1, 2, 3, 5, 7}, 70] (* Vincenzo Librandi, Aug 08 2015 *)
PROG
(Magma) [n*(n-1) div 8: n in [0..70]]; // Vincenzo Librandi, Aug 08 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved